Classifications

• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08J—WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
  • C08J5/00—Manufacture of articles or shaped materials containing macromolecular substances
  • C08J5/18—Manufacture of films or sheets
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08K—Use of inorganic or non-macromolecular organic substances as compounding ingredients
  • C08K3/00—Use of inorganic substances as compounding ingredients
  • C08K3/01—Use of inorganic substances as compounding ingredients characterized by their specific function
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08K—Use of inorganic or non-macromolecular organic substances as compounding ingredients
  • C08K5/00—Use of organic ingredients
  • C08K5/04—Oxygen-containing compounds
  • C08K5/13—Phenols; Phenolates
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
  • C08L23/00—Compositions of homopolymers or copolymers of unsaturated aliphatic hydrocarbons having only one carbon-to-carbon double bond; Compositions of derivatives of such polymers
  • C08L23/02—Compositions of homopolymers or copolymers of unsaturated aliphatic hydrocarbons having only one carbon-to-carbon double bond; Compositions of derivatives of such polymers not modified by chemical after-treatment
  • C08L23/10—Homopolymers or copolymers of propene
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
  • C08L67/00—Compositions of polyesters obtained by reactions forming a carboxylic ester link in the main chain; Compositions of derivatives of such polymers
  • C08L67/02—Polyesters derived from dicarboxylic acids and dihydroxy compounds
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
  • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
  • Y10T428/00—Stock material or miscellaneous articles
  • Y10T428/249921—Web or sheet containing structurally defined element or component
  • Y10T428/249953—Composite having voids in a component [e.g., porous, cellular, etc.]
  • Y10T428/249978—Voids specified as micro
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
  • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
  • Y10T428/00—Stock material or miscellaneous articles
  • Y10T428/249921—Web or sheet containing structurally defined element or component
  • Y10T428/249953—Composite having voids in a component [e.g., porous, cellular, etc.]
  • Y10T428/249978—Voids specified as micro
  • Y10T428/249979—Specified thickness of void-containing component [absolute or relative] or numerical cell dimension
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
  • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
  • Y10T428/00—Stock material or miscellaneous articles
  • Y10T428/249921—Web or sheet containing structurally defined element or component
  • Y10T428/249953—Composite having voids in a component [e.g., porous, cellular, etc.]
  • Y10T428/249978—Voids specified as micro
  • Y10T428/24998—Composite has more than two layers
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
  • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
  • Y10T428/00—Stock material or miscellaneous articles
  • Y10T428/249921—Web or sheet containing structurally defined element or component
  • Y10T428/249953—Composite having voids in a component [e.g., porous, cellular, etc.]
  • Y10T428/249986—Void-containing component contains also a solid fiber or solid particle
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
  • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
  • Y10T428/00—Stock material or miscellaneous articles
  • Y10T428/249921—Web or sheet containing structurally defined element or component
  • Y10T428/249953—Composite having voids in a component [e.g., porous, cellular, etc.]
  • Y10T428/249987—With nonvoid component of specified composition
  • Y10T428/249991—Synthetic resin or natural rubbers
  • Y10T428/249992—Linear or thermoplastic
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
  • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
  • Y10T428/00—Stock material or miscellaneous articles
  • Y10T428/249921—Web or sheet containing structurally defined element or component
  • Y10T428/249953—Composite having voids in a component [e.g., porous, cellular, etc.]
  • Y10T428/249987—With nonvoid component of specified composition
  • Y10T428/249991—Synthetic resin or natural rubbers
  • Y10T428/249992—Linear or thermoplastic
  • Y10T428/249993—Hydrocarbon polymer
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
  • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
  • Y10T428/00—Stock material or miscellaneous articles
  • Y10T428/31504—Composite [nonstructural laminate]
  • Y10T428/31855—Of addition polymer from unsaturated monomers
  • Y10T428/31909—Next to second addition polymer from unsaturated monomers
  • Y10T428/31913—Monoolefin polymer

Definitions

• the present invention relates to a porous resin film excellent in ink drying property.
• the present invention relates also to a recording medium excellent in ink-jet printing property and capable of producing thereon a high-definition image.
• ink-jet printers are widely employed in both fields of professional use and public use.
• Ink-jet printers are advantageous in various aspects such that they can readily be multi-colored and can readily be expanded in image size, and that they require only a low printing cost.
• ink-jet printers using a water-base ink which is less causative of environmental and safety problems as compared with an oil-base ink, form the mainstream of recent printers.
• the ink-jet printers are widely used also as a means for obtaining a hard copy which includes processed image as well as character information. Thus there is a growing need for finer image after the printing.
• Fineness of the image is governed by drying property of an ink applied on a recording medium.
• one recording medium previously printed may be overlaid with another recording medium. If an ink on the previously printed recording medium dries insufficiently, the ink may be caught by the overlaid recording medium, which result in a stained image.
• One popular method for enhancing the image fineness is such that using a recording medium which comprises a base layer made of synthetic paper, plastic film or pulp paper and an ink accepting layer coated thereon containing a hydrophilic resin or inorganic fine powder (Japanese Laid-Open Patent Publications Nos. 3-82589 and 9-216456). While the method is successful in yielding a high-definition image when the ink discharge is relatively small, the method may cause insufficient drying of the ink when the discharge is relatively large. Increasing the thickness of the coated layer, which is one proposed countermeasure for such problem, will raise the cost and thus ruin the practicability as an ink-jet recording medium.
• Another proposal relates to an ink-jet recording medium in which an ink accepting layer mainly composed of a hydrophilic resin is formed by the heat lamination process or the extrusion lamination process (Japanese Laid-Open Patent Publications 8-12871, 9-1920 and 9-314083.
• Such ink-jet recording medium has also been unsatisfiable since the medium cannot produce thereon a desirable image when the ink discharge is relatively large.
• the present inventors found out after the extensive studies to accomplish the foregoing objects that using a porous film comprising a water-soluble or water-swelling hydrophilic resin compounded with an inorganic or organic fine powder, or a stacked material having such porous film as a surface layer thereof can provide a desirable recording medium excellent in ink drying property and suitable for printing process, such as ink-jet printing using a water-base ink, which led us to propose the present invention.
• porous resin film (i) including 30 to 90 wt % of a thermoplastic resin that includes a hydrophilic thermoplastic resin component; and 70 to 10 wt % of an inorganic or organic fine powder.
• the present invention also provides a stacked material which includes a base layer and the foregoing porous resin film stacked on at least one side of such base layer.
• the base layer preferably includes a resin film (referred to as “resin film (ii)”, hereinafter) which contains 40 to 100 wt % of a thermoplastic resin and 60 to 0 wt % of an inorganic or organic fine powder.
• resin film (ii) is preferably stretched.
• the present invention still also provides a recording medium using the foregoing porous resin film or the stacked material, in particular the one for ink-jet printing.
• a porosity of the porous resin film (i) is 10% or above and preferably within a range from 20 to 80%. It is recommendable that the surface of the porous resin film (i) has a contact angle to water of 110° or less, and it is more preferable that difference between a maximum value and a minimum value of the contact angle to water is adjusted within 30°.
• the thermoplastic resin preferably comprises 5 to 100 weight parts of the hydrophilic thermoplastic resin component per 100 weight parts of a non-hydrophilic resin component.
• the non-hydrophilic thermoplastic resin component is preferably a polyolefin-base resin, and the hydrophilic thermoplastic resin component is preferably an alkylene oxide-base polymer.
• the inorganic or organic fine powder preferably has an average grain size of 0.1 to 10 ⁇ m.
• the porous resin film (i) is preferably stretched.
• the resin film (ii) used as a base layer of the stacked material may be composed of any one of a non-hydrophilic thermoplastic resin, a hydrophilic thermoplastic resin and a mixture of a non-hydrophilic thermoplastic resin and a hydrophilic thermoplastic resin, or a mixture of any one of such resin with an inorganic or organic fine powder.
• the porous resin film (i) of the present invention is characterized in that containing 0 to 90 wt % of a thermoplastic resin containing a hydrophilic thermoplastic resin component; and 70 to 10 wt % of an inorganic or organic fine powder.
• Such porous resin film (i) of the present invention is excellent in ink drying property, so that it is most preferably used for a recording medium such as an ink-jet recording medium.
• the base layer is preferably a resin film (ii) which contains 40 to 100 wt % of a thermoplastic resin and 60 to 0 wt % of an inorganic or organic fine powder.
• thermoplastic resin composing the porous resin film (i) and the resin film (ii).
• the species of the non-hydrophilic thermoplastic resin component composing the porous resin film (i) and the resin film (ii) may be the same or differ with each other.
• non-hydrophilic thermoplastic resin component examples include polyolefinic resins such as ethylene-base resins including high density polyethylene and middle density polyethylene, propylene-base resins, poly(4-methyl-1-pentene), ethylene-cyclic olefin copolymer; polyamide-base resins such as 6-nylon, 6,6-nylon and 6, T-nylon; thermoplastic polyester-base resins such as polyethylene terephthalate and copolymer thereof, polybutylene terephthalate and copolymer thereof, aliphatic polyester; polycarbonate, atactic polystyrene and syndiotactic polystyrene. Among these, most preferable is a non-polar polyolefinic resins.
• polyolefinic resins such as ethylene-base resins including high density polyethylene and middle density polyethylene, propylene-base resins, poly(4-methyl-1-pentene), ethylene-cyclic olefin copolymer
• propylene-base resins are preferably used from viewpoints of chemical resistance and cost.
• the propylene-base resin may be an isotactic homopolymer or syndiotactic homopolymer made solely of propylene units. It is also allowable to use polypropylene-base copolymers having a variety of stereoregularities obtained by co-polymerizing propylene with ⁇ -olefin(s) such as ethylene, 1-butene, 1-hexene, 1-heptene or 4-methyl-1-pentene.
• the copolymer may be of binary system, ternary system or higher, and may be a random copolymer or block copolymer.
• the propylene-base resin is preferably used as being mixed with 2 to 25 wt % of a resin having a melting point lower than that of a propylene homopolymer.
• a resin having a melting point is exemplified as high-density or low-density polyethylene.
• hydrophilic thermoplastic resin component used for the porous resin film (i) and the resin film (ii) so far as such resin component can dissolve or swell in water, and can exhibit plasticity at the room temperature or above.
• the hydrophilic thermoplastic resins used for the porous resin film (i) and the resin film (ii) may be the same or differ with each other.
• hydrophilic thermoplastic resin component examples include polyvinyl-base resins such as synthetic polyvinyl alcohol and copolymer or crosslinked product thereof, and polyvinyl pyrrolidone and copolymer thereof; polyacrylic resins or salts thereof (for example, sodium salt, potassium salt, lithium salt and primary to quaternary ammonium salts) such as polymer, copolymer or crosslinked product of acrylic, methacrylic or maleic ester containing a hydroxyalkyl group such as 2-hydroxyethyl group or 2-hydroxypropyl group, polyacrylamide or copolymer thereof, hydrolysate of polymer or crosslinked polymer of acrylonitrile, and polymer, copolymer or crosslinked product of acrylic or methacrylic acid; polymaleic acid, maleic acid copolymer, crosslinked product thereof or salts thereof (for example, sodium salt, potassium salt, lithium salt and primary to quaternary ammonium salts), and hydrolysate of vinyl acetate-methyl methacrylate cop
• the hydrophilic resin which can dissolve into water or swell at a water absorption factor of 5 or above, more advantageously 8 to 50, within 30 minutes at the room temperature.
• the water absorption factor is defined by processing the hydrophilic resin into a test piece of approx. 0.1 mm thick by means of extrusion from a T-die or heat press forming, then immersing the test piece into a distilled water at the room temperature (25°) for 30 minutes to allow water absorption, and then dividing post-absorption weight of the test piece by pre-absorption weight.
• natural polymers such as gum arabic, tragacanth gum, corn starch, wheat starch and collagen are not applicable to the hydrophilic thermoplastic resin component since they are difficult to function at a high temperature required for melting the plastics.
• polyalkylene oxide-base resins it is preferable to choose polyalkylene oxide-base resins since they can exhibit plasticity at the room temperature or above, and film formation of which is relatively simple.
• polyalkylene oxide-base resins applicable to the present invention include reaction product of alkylene oxide with a dibasic acid or a multi-basic acid having three or more carboxylic group; ester bond-containing, polyester-base polyalkylene oxides typified by a reaction product of polyalkylene oxide compound with a dicarboxilic acid compound, a lower alkyl ester compound thereof, a carboxylic acid having three or more carboxyl groups, or with a lower alkyl ester compound thereof; urethane bond-containing, polyurethane-base polyalkylene oxides typified by a reaction product of polyalkylene oxide compound with a compound having two or more isocyanate groups; carbonate bond-containing polyalkylene oxides typified by a reaction product of polyalkylene oxide compound with a
• ester bond-containing polyalkylene oxides are preferable from the viewpoint of achieving a higher level of mixing and dispersion properties with the non-hydrophilic thermoplastic resin component.
• alkylene oxides to be used are not specifically limited, and typical examples thereof include ethylene oxide, propylene oxide, 1,2-epoxybutane, 1,2-epoxypentane, 1,2-epoxyhexane and other ⁇ -olefin oxides having the carbon number of up to 30. Among these more preferable are ethylene oxide, propylene oxide, 1,2-epoxybutane and 1,2-epoxyhexane. These alkylene oxides may be used individually or in any combination of two or more thereof. For the case using two or more alkylene oxides, the alkylene oxides may sequentially be reacted one by one, or may be reacted en bloc by mixing two or more species.
• the species of the alkylene oxide it is preferable to use a polymer or copolymer of the foregoing alkylene oxide having a weight-average molecular weight of 5,000 to 30,000.
• a polyalkylene oxide compound having a weight-average molecular weight of 5,000 or above will upgrade the film forming property, and using a polyalkylene oxide compound having a weight-average molecular weight of 30,000 or below will advantageously improve productivity of such resin since the addition reaction of the alkylene oxide proceeds at a relatively high speed.
• the polyalkylene oxide compound can be obtained by addition polymerization of alkylene oxides.
• One preferable example of such polyalkylene oxide compound is such that being obtained by additionally polymerizing an organic compound having two active hydrogen atoms with the foregoing alkylene oxide.
• organic compound having two active hydrogen atoms examples include ethylene glycol, diethylene glycol, propylene glycol, dipropylene glycol, 1,4-butanediol, 1,6-hexanediol, neopentyl glycol, bisphenol-A, polytetramethylene glycol, alicyclic diol such as 1,4-di(hydroxymethyl)cyclohexane, and amines such as butylamine, laurylamine, octyl amine, cyclohexylamine and aniline, while being not limited thereto.
• ethylene glycol diethylene glycol, propylene glycol, dipropylene glycol, 1,4-butanediol and 1,6-hexanediol.
• Preferable polyalkylene oxide compound is such that being obtained by additionally polymerizing an organic compound having two active hydrogen atoms with ethylene oxide, then with a C 4 or larger alkylene oxide, and further with ethylene oxide.
• polyalkylene oxide compound can further be reacted with a dicarboxylic acid compound, to thereby yield a non-hydrophilic resin component, in particular a polyalkylene oxide-base resin relatively excellent in compatibility with a polyolefmic resin.
• a film obtained by mixing such polyalkylene oxide-base resin and polyolefinic resin can ensure a desirable ink absorption in the printing process, and can thus improve uniformity in the absorption.
• Structure of the carboxylic acid or lower alkyl ester compound thereof to be reacted with the polyalkylene oxide compound is not specifically limited so far as the compound has within the molecule thereof two or more, and more preferably two, carboxylic group or derived group therefrom.
• Specific examples thereof include C 6 to C 36 , more preferably C 8 to C 24 , linear, branched, alicyclic, or aromatic di- or tri-carboxylic acid and lower alkyl ester of such di- or tri-carboxylic acid.
• examples thereof include sebacic acid, 1,10-decamethylene dicarboxylic acid, 1,14-tetradecamethylene dicarboxylic acid, 1,18-octadecamethylene dicarboxylic acid, 1,32-dotriacontamethylene dicarboxylic acid, cyclohexane dicarboxylic acid, phthalic acid, terephthalic acid, isophthalic acid, various isomers of naphthalene dicarboxylic acid, 4,4′-biphenylene dicarboxylic acid and lower alkyl esters of these compounds.
• these preferable is either one of a C 12 to C 36 linear dicarboxylic acid or lower alkyl ester thereof.
• C 12 to C 36 saturated linear aliphatic dicarboxylic acid C 12 to C 36 unsaturated linear aliphatic dicarboxylic acid or lower alkyl esters thereof can preferably be used. Still more preferable among these compounds are C 12 to C 26 linear dicarboxylic acid and lower alkyl ester thereof, and in particular C 16 to C 24 linear dicarboxylic acid and lower alkyl ester thereof.
• Specific examples of such C 12 to C 36 linear dicarboxylic acid include 1,10-decamethylene dicarboxylic acid, 1,14-tetradecamethylene dicarboxylic acid, 1,18-octadecamethylene dicarboxylic acid and 1,32-dotriacontamethylene dicarboxylic acid.
• lower alkyl ester examples include methyl ester, dimethyl ester, ethyl ester, diethyl ester, propyl ester and dipropyl ester of these dicarboxylic acids. These compounds may be used individually or in any combination of two or more thereof.
• Particularly preferable alkylene oxide-base polymer can be obtained by co-polymerizing polyalkylene oxide with a C 12 to C 36 aliphatic dicarboxylic acid or a lower alkyl ester thereof to thereby adjust an overall molecular weight to 20,000 to 400,000, more preferably to 80,000 to 200,000; where the polyalkylene oxide is obtained by additionally polymerizing an organic compound having two active hydrogen atoms, which can be selected from ethylene glycol, diethylene glycol, propylene glycol, dipropylene glycol and 1,4-butanediol, with an alkylene oxide mainly composed of ethylene oxide and having additionally polymerized therewith any one of propylene oxide, 1,2-epoxybutane and 1,2-epoxyhexane to thereby achieve a molecular weight of 10,000 to 30,000.
• an organic compound having two active hydrogen atoms which can be selected from ethylene glycol, diethylene glycol, propylene glycol, dipropylene glycol and 1,4-butan
• the hydrophilic resin component is preferably mixed in an amount of 5 to 100 weight parts per 100 weight parts of the non-hydrophilic thermoplastic resin component from the viewpoint of properly adjusting the a contact angle to water to thereby improve ink drying property. More preferable mixing relates to 5 to 100 weight parts, and more preferably 10 to 60 weight parts, of the polyalkylene oxide-base resin per 100 weight parts of the polyolefinic resin.
• a dispersion modifier may preferably be added when the hydrophilic thermoplastic resin component and non-hydrophilic thermoplastic resin component are kneaded under fusion.
• the dispersion modifier is beneficial in improving the dispersion property and dispersion stability, and is valuable in reducing difference between maximum and minimum values of surface contact angle, to thereby equalize the absorption of water-base fluid.
• dispersion modifier examples include those of polar resin-base such as epoxy group-containing resin, acid modified resin, hydroxy group-containing resin and amino modified resin; and phosphorus-containing compound such as phosphite compound and phosphonate compound.
• the polar resin-base dispersion modifier include ethylene-glycidyl methacrylate copolymer, ethylene-vinyl acetate-glycidyl methacrylate copolymer, ethylene-methyl methacrylate-glycidyl methacrylate copolymer, ethylene-ethyl methacrylate-glycidyl methacrylate copolymer, ethylene-ethyl acrylate-glycidyl methacrylate copolymer, glycidyl methacrylate graft modified polypropylene, glycidyl methacrylate-styrene graft modified polypropylene, epoxy-modified polybutadiene, epoxy-modified polyisoprene, (partial) epoxy-modified styrene-butadiene block copolymer, (partial) epoxy-modified styrene-butadiene-styrene block copolymer, (partial) epoxy-mod
• ethylene-glycidyl methacrylate copolymer ethylene-vinyl acetate-glycidyl methacrylate copolymer, glycidyl methacrylate graft modified polypropylene, and partial epoxy-modified styrene-butadiene-styrene block copolymer.
• phosphorus-containing dispersion modifier examples include bis(2,4-dimethylphenyl)pentaerythritol diphosphite, bis(2,6-dimethylphenyl)pentaerythritol diphosphite, bis(2,3,6-trimethylphenyl)pentaerythritol diphosphite, bis(2-tert-butylphenyl)pentaerythritol diphosphite, bis(3-tert-butylphenyl)pentaerythritol diphosphite, bis(4-tert-butylphenyl)pentaerythritol diphosphite, bis(2,4-di-tert-butylphenyl)pentaerythritol diphosphite, bis(2,6-di-tert-butylphenyl)pentaerythritol diphosphite, bis(2,4,6-tri-
• bis(2,4-di-tert-butylphenyl)pentaerythritol diphosphite bis(2,6-di-tert-butyl-4-methylphenyl)pentaerythritol diphophite, distearylpentaerythritol diphosphite, bis(nonylphenyl)pentaerythritol diphosphite, tetrakis (2,4-di-tert-butylphenyl)-4,4′-bisphenylene diphosphonate and any mixtures thereof.
• an amount of use of the polar resin-base dispersion modifier is generally 0.1 weight parts or above per 100 weight parts of the non-hydrophilic thermoplastic resin component, more preferably 0.5 to 30 weight parts, and still more preferably 1 to 15 weight parts.
• An amount of use of the phosphorus-containing dispersion modifier is generally 0.01 weight parts or above per 100 weight parts of the non-hydrophilic thermoplastic resin component, more preferably 0.1 to 20 weight parts, and still more preferably 0.2 to 3 weight parts.
• the porous resin film (i) of the present invention may contain a decomposition product (for example through hydrolysis or thermal decomposition) generated from such polar resin-base or phosphorus-containing dispersion modifier.
• the inorganic fine powder may be of, for example, heavy calcium carbonate, precipitated calcium carbonate, agglomerative precipitated calcium carbonate, clay, talc, titanium oxide, barium sulfate, zinc oxide, magnesium oxide, diatom earth or silicon oxide.
• the organic fine powder has a different origin with that for the thermoplastic resin composing the porous resin film (i), and is preferably selected from those having a melting point or glass transition point higher than that of the thermoplastic resin to be used and incompatible therewith in consideration of pore formation.
• the organic fine powder may be of, for example, polyethylene terephthalate, polybutylene terephthalate, polyamide, polycarbonate, polyethylene naphthalate, polystyrene, melamine resin, polyethylene sulfide, polyimide, polyethyl ether ketone, polyphenylene sulfite, polymer of methacrylate or acrylate, or any copolymer containing any of such compounds.
• the fine powder can be dispersed into the porous resin film (i) by a non-limitative method. That is, the fine powder may be synthesized in a fine powdery form after the polymerization and then be added with other components, or may previously be dispersed in a finer form before being kneaded under fusion with other components.
• any one of the fine powder can be selected or two or more species thereof can be combined.
• the combination of two or more species also allows mixed use of an organic fine powder and an inorganic fine powder.
• heavy calcium carbonate, clay and diatom earth are particularly preferable for their inexpensiveness and pore forming property.
• An average grain size of the fine powder used for the porous resin film (i) resides in a range from 0.01 to 10 ⁇ m, and more preferably from 0.1 to 3 ⁇ m. Selecting the grain size within such range will allow formation of sufficient amount of properly-sized pores by stretching and will effectively prevent wrinkle generation on the film. In particular for the porous resin film (i), such selection will allow the film surface to have micro cracks, which can enhance the ink drying property and effectively prevent stain on the film during the printing. It is now favorable to suppress the content of coarse grain (with a grain size of 44 ⁇ m or above, for example) as low as 10 ppm or below so as to prevent projections from being formed on the surface of the porous resin film (i).
• the porous resin film (i) and the resin film (ii) composing the base layer may have a desirable color using an inorganic or organic coloring pigment. It is also preferable to add an antioxidant or ultraviolet stabilizer to the porous resin film (i) of the present invention if it is intended for use as a durable material.
• an organic fine powder proper selection of a type and amount of addition of a solubilizing agent is critical since they govern the particle morphology of the organic fine powder.
• Polar group-containing polyolefin is a preferable example of such solubilizing agent.
• An amount of addition of the solubilizing agent is generally 0.5 to 10 weight parts per 100 weight parts of the organic fine powder.
• the porous resin film (i) comprises 30 to 90 wt %, more preferably 35 to 60 wt %, of a thermoplastic resin containing a hydrophilic thermoplastic resin component; and 70 to 10 wt %, more preferably 65 to 40 wt %, of an inorganic or organic fine powder.
• the content of the inorganic or organic fine powder exceeding 70 wt % tends to embrittle the surface layer of the film and tends to cause omission of such fine powder upon mechanical impact, and the content less than 10 wt % tends to degrade the ink drying property. Stretching the porous resin film (i) while keeping the parameters within the above ranges will ensure excellent ink absorbing and drying properties and mechanical strength of such film.
• the surface contact angle to water of the porous resin film (i) of the present invention is 110° or below, more preferably within a range from 20 to 100°, and still more preferably within a range from 20° to 80°.
• a range from 45° to 80° is particularly recommendable for the film for use in ink-jet printing.
• the surface contact angle to water exceeding 110° will sometimes result in insufficient fluid penetration by a water-base ink or a glue using a water-base medium.
• too small contact angle is not always desirable in order to properly balance lateral spreading of a droplet of a water-base ink in a direction parallel to the film surface and vertical penetration thereof along the direction of the film thickness.
• the surface contact angle of 110° or below is substantially effective in improving printing property in the ink-jet printing.
• surface contact angle to water is obtained by placing a droplet of pure water on the film surface, and measuring the contact angle using a commercially available contact angle gauge. The measurement is repeated 10 times for one species of the film, where an unwet new sample film is subjected to each measurement, and the contact angle to water is calculated as an average of the values from ten times of the measurement.
• Model CA-D a product of Kyowa Kaimen Kagaku K. K., is one example of such commercially available contact angle gauge for use in the measurement.
• “Difference between maximum and minimum values of the contact angle to water” as described in the context of this specification represents difference between a maximum value and a minimum value obtained from 10 times of such measurement.
• the difference between the maximum and minimum values is preferably 30° or less, more preferably 20° or less, and still more preferably 10° or less.
• the thickness of the porous resin film (i) of the present invention is not limitative, and can properly be selected depending on a required level of the absorption property. Typical thickness is 10 to 500 ⁇ m, more preferably 20 to 350 ⁇ m, and still more preferably 25 to 200 ⁇ m.
• the porous resin film (i) of the present invention has a porous structure having micro pores, where the porosity of such porous resin film (i) is preferably 10% or above, more preferably 20 to 80%, still more preferably 20 to 75%, and most preferably 30 to 65%. Selecting the porosity at 10% or above can upgrade the ink absorbing and drying properties.
• the porous resin film (i) having a porosity of 80% or below ensures an almost desirable material strength of the film.
• ⁇ 0 denotes the pre-stretching density of the film
• ⁇ denotes the post-stretching density of the film.
• porous resin film (i) of the present invention can be fabricated by various combination of processes known to those skilled in the art. Any porous resin film or recording material fabricated by any process will be within a scope of the present invention so far as conditions described in claim 1 are satisfied.
• Processes for fabricating the porous resin film (i) of the present invention preferably include process steps necessary for achieving the porosity of 10% or above.
• Such porosity is attainable by film stretching method based on pore generation through stretching, foaming method based on use of a foaming agent, and a method using pore-containing grains, among which the film stretching method is most preferable.
• the porous resin film (i) and the base layer may be stacked after being individually stretched, or may be stretched en bloc after being stacked. Also the porous resin film (i) and the base layer can be stacked or stretched in a series of same processes.
• a preferable fabrication process relates to such that having a step for stacking the porous resin film (i) and the resin film (ii) as a base layer; and a step for stretching the obtained stack en bloc, which is simpler and costless as compared with the case of separate stretching before the stacking.
• This also enables more simple control of the pores generated in the porous resin film (i) and the resin film (ii).
• controlling the amount of pores generated by the stretching in the porous resin film (i) larger than in the resin film (ii) allows maximum use of such porous resin film (i) as a layer for improving the ink drying property.
• the stretching may be effected by a variety of known methods.
• the stretching temperature can properly be selected within a known temperature range according to nature of the thermoplastic resin to be employed. That is, for the case an amorphous thermoplastic resin is employed, the stretching temperature will be equal to or higher than the glass transition point of such resin; and for the case a crystalline thermoplastic resin is employed, the stretching temperature will be within a range from the glass transition point of the amorphous portion thereof to the melting point of the crystalline portion thereof. More specifically, a temperature lower by 2 to 60° than the melting point of a thermoplastic resin to be employed is preferable.
• Applicable means for the stretching include longitudinal stretching based on difference in the peripheral speeds between the roll groups, transverse stretching using a tenter oven, rolling, and simultaneous biaxial stretching based on a combined use of a tenter oven and a linear motor.
• the stretching factor there is no special limitation on the stretching factor, and the factor can properly be determined depending on purpose of use of the porous resin film of the present invention and properties of the thermoplastic resin employed.
• typical factor for the uniaxial stretching is within a range from approx. 1.2 to 12 times, and preferably 2 to 10 times; and areal factor for the biaxial stretching is within a range from 1.5 to 60 times, and preferably 10 to 50 times.
• typical factor for the uniaxial stretching is within a range from approx. 1.2 to 10 times, and preferably 2 to 7 times; and areal factor for the biaxial stretching is within a range from 1.5 to 20 times, and preferably 4 to 12 times.
• the stretching speed is preferably 0.1 to 350 m/min. Annealing at a high temperature may optionally be allowable.
• the porous resin film (i) of the present invention may be used without further processing, or may be used in a form stacked at least on one surface of a separate base layer.
• Possible materials for composing the base layer include transparent or opaque film such as polyester film, polyamide film and polyolefin film; plastic board, pulp paper, non-woven fabric, cloth, wood board and metal plate.
• the thickness of the base layer composing the stacked material is not specifically limited, and is typically set in a range from 5 to 1,000 ⁇ m, more preferably from 20 to 500 ⁇ m. Also the thickness of the stacked material is not specifically limited, and can properly be selected according to the purpose of use. A typical range of the thickness is 15 to 2,000 ⁇ m, more preferably 20 to 500 ⁇ m, and still more preferably 25 to 350 ⁇ m.
• the porous resin film (i) of the present invention is preferably composed to provide a recording material by being added with a proper functional layer as described later in the Examples.
• a typical recording medium is obtained by forming the porous resin film (i) of the present invention on a base layer made of a thermoplastic film.
• a recording medium having on the surface thereof the porous resin film (i) of the present invention is beneficial in particular for use in ink-jet printing. While species for composing the base layer is not specifically limited, a desirable example thereof relates to a film containing a polypropylene-base resin and an inorganic fine powder.
• the recording medium thus obtained by stacking the porous resin film (i) of the present invention with other film will have a total thickness of approx. 60 ⁇ m to 1 mm.
• the base layer of the stacked material is preferably composed of the resin film (ii).
• the resin and inorganic or organic fine powder for use in the resin film (ii) may be used as a single species selected from the foregoing non-hydrophilic thermoplastic resins or the foregoing inorganic or organic fine powders, or in combination of two or more species selected therefrom. It is also allowable to use a non-hydrophilic thermoplastic resin component as being mixed with a hydrophilic thermoplastic resin component, where such resin components may be the same with those used in the porous resin film (i).
• thermoplastic resin component For the case of the mixed use of a non-hydrophilic and hydrophilic thermoplastic resin components for the resin film (ii), it is preferable to mix 10 to 100 weight parts of the hydrophilic thermoplastic resin component per 100 weight parts of the non-hydrophilic thermoplastic resin component.
• the resin film (ii) contains the thermoplastic resin component in an amount of 40 to 100 wt %, more preferably 40 to 85%; and contains the inorganic or organic fine powder in an amount of 60 to 0 wt %, more preferably 60 to 15 wt %.
• the content of the organic or inorganic fine powder exceeding 80 wt % will result in difficulty in fabricating the resin film (ii) having a uniform thickness, and the content less than 15 wt % will result in insufficient pore formation and higher cost.
• the grain size of the inorganic or organic fine powder for use in the resin film (ii) is preferably within a range from 0.1 to 10 ⁇ m, and more preferably from 0.6 to 3 ⁇ m.
• the porous resin film (i) or the stacked material using such film can optionally be subjected to surface oxidation treatment.
• the surface oxidation treatment may enhance the hydrophilicity or absorption property of the film surface, and may improve coating property or adhesion property of an ink fixing agent and ink acception layer.
• the surface oxidation treatment can specifically be effected by corona discharge treatment, flame treatment, plasma treatment, glow dischrage treatment and ozone treatment. Among these, preferable are corona treatment and flame treatment, and the former is more preferable.
• the energy of, for example, the corona treatment is 600 to 12,000 J/m 2 (10 to 200 W ⁇ min/m 2 ), and more preferably 1,200 to 9,000 J/m 2 (20 to 180 W ⁇ min/m 2 ). At least an energy of 600 J/m 2 (10 W ⁇ min/m 2 ) is necessary to obtain sufficient effect of the corona treatment, and an energy of 12,000 J/m 2 (200 W ⁇ min/m 2 ) is sufficient enough since the effect will saturate above 12,000 J/m 2 .
• the energy of the flame treatment is 8,000 to 200,000 J/m 2 , and more preferably 20,000 to 100,000 J/m 2 . At least an energy of 8,000 J/m 2 is necessary to obtain distinct effect of the flame treatment, and an energy of 200,000 J/m 2 is sufficient enough since the effect will saturate above 200,000 J/m 2 .
• the porous resin film (i) can have on the outermost portion thereof a coloring material fixation layer for fixing coloring materials such as dyes and pigments.
• the coloring material fixation layer is responsible for shaping ink dots into exact circles to thereby ensure sharp image, and for preventing migration of the coloring material due to water or moisture.
• the coloring material fixation layer is particularly beneficial when the porous resin film (i) of the present invention is intended for use as a recording medium for the ink-jet printing.
• the coloring material fixation layer can be formed by coating or lamination.
• a cationic hydrophilic resin and fine powder is preferable in order to upgrade the coloring material fixation property.
• cationic hydrophilic resin is such that having cationic groups such as amino groups, modified groups thereof or quaternary ammonium salt groups on the principal chains or side chains of the polymer.
• the porous resin film (i) of the present invention can also be subjected to various printings other than ink-jet printing according to purposes of use, where types and methods for the printing are not limitative. That is, the printing can be effected by any of known methods including gravure printing using an ink which contains pigment dispersed in a known vehicle, water-base flexography, and silk screen printing. Other applicable methods relate to metal vapor deposition, gross printing and mat printing. Patterns to be printed may properly be selected from natural or abstract items such as animals, landscape, lattice or polka dots.
• the obtained pellets were melted at 230° C. in a press forming machine, compressed at 50 kgf/cm 2 , cooled to 30° C., to thereby obtain a sheet of 120 mm ⁇ 120 mm in size and 1 mm thick. A density of the sheet was found to be 1.4 g/cm 3 .
• the sheet was heated to 158° C. (temperature a1) in a small-sized biaxial stretching machine (product of Iwamoto Seisakusho K. K.), unidirectionally stretched by 6 times, cooled to 90° C. (temperature b1) by cold air blow, to thereby obtain a porous resin film having a thickness of 310 ⁇ m and a density of 0.95 g/cm 3 .
• the porosity of the sheet was 32%.
• Porous resin films were fabricated similarly to Example 1, except that components listed in Table 1 were used instead.
• Dispersion modifiers used in Examples 6 to 8 are ethylene-glycidyl methacrylate copolymer (amount of co-polymerization of glycidyl methacrylate is approx. 12%; product name “Bondfast ®- 2E” from Sumitomo Chemical; abbrev. EX1), epoxy-modified styrene-butadiene block copolymer (product name “Epofriend ® A- 1005” from Daicel Chemical Industries, Ltd.; epoxy equivalent is ca. 2,000; abbrev.
• Example 9 The stretching factor in Example 9 was 6 simultaneously in the longitudinal and transverse directions.
• Example 10 and Comparative Example 3 the surface of the porous resin film was subjected to corona discharge treatment at an applied energy density of 80 W ⁇ min/m 2 using a corona discharge treatment apparatus (product name “Label Compact discharge treatment system” from Ahlbrandt System GmbH).
• Polyalkylene oxide-base resin (abbrev. PEPO2) used in Example 11 is an ester formed between tetradecamethylene dicarboxylic acid and a copolymer of approx. 85% of ethylene oxide and approx 15% of butylene oxide and having a weight-average molecular weight of approx. 20,000, which has an overall molecular weight of approx. 120,000 and a 30-minute water absorption factor of approx. 13 g/g.
• Polyalkylene oxide-base resin (abbrev. PEPO3) used in Example 12 is an ester formed between phthalic acid and a copolymer of approx. 90% of ethylene oxide and approx 10% of propylene oxide, which has an overall molecular weight of approx. 130,000 and dissolves into water within 30 minutes.
• composition [A] was kneaded under fusion together with 0.1 weight parts of 4-methyl-2,6-di-tert-butylphenol and 0.05 weight parts of Irganox ® 1010 (product of Ciba Geigy), both of which are antioxidants added per total 100 weight parts of the resin components and calcium carbonate powder.
• the composition [A] was then extruded from a T-die connected to an extrusion machine (temperature set at 250° C.), then cooled using a cooling apparatus, to thereby obtain an unstretched sheet.
• the unstretched sheet was then heated to 140° C., and stretched by 4.5 times in the longitudinal direction to thereby obtain a stretched sheet.
• Example 13 The surface of the stacked product obtained in Example 13 was subjected to corona discharge treatment. Conditions for the corona discharge treatment were similar to those in Example 10 except for an applied energy density set at 90 W ⁇ min/m 2 .
• a stretched sheet was obtained similarly to Example 13 except that the components of the composition “A” were altered as 70 wt % of polypropylene, 5 wt % of high-density polyethylene, 5 wt % of polyalkylene oxide-base resin same as that used in Example 1, and 20 wt % of calcium carbonate having an average grain size of 1.5 ⁇ m.
• the surface of thus obtained stacked product was subjected to corona discharge treatment.
• Conditions for the corona discharge treatment were similar to those in Example 10 except for an applied energy density set at 60 W ⁇ min/m 2 .
• porosity ⁇ ⁇ ( % ) 100 ⁇ ( ⁇ 0 - ⁇ ) ⁇ 0
• ⁇ 0 is the pre-stretching density of the porous resin film
• ⁇ is the post-stretching density of the porous resin film.
• Another method is such that embedding the porous resin film with an epoxy resin, solidifying the epoxy resin, and slicing the resultant solid using a microtome in a direction parallel to the stretching direction and normal to the major plane of the film.
• the cut plane of the slice is metallized and the embedded porous resin film was observed under an electron microscope at a 2,000 ⁇ magnification. Pores in an observation area were contoured on a tracing film and marked by filling the contour, then the obtained pattern was subjected to image processing using an image analyzer (LUZEX IID, product of Nireco Corporation). Porosity was determined based on the areal ratio of the pores.
• Color charts for evaluation (2 cm ⁇ 2 cm monochromatic 50% printing and monochromatic 100% printing, and 2 cm ⁇ 2 cm multi-color 200% printing) were developed and printed on the porous resin film using pigment inks (yellow, magenta, cyan, and black) and an ink-jet printer (Model JP2115, product of Graphtec Corporation). Filter paper was periodically pressed to the printed portion and whether the ink migrates back to the filter paper or not was checked. Time point when the ink migration terminates was recorded and the ink drying performance was assessed based on the following criteria:
• Non-uniformity in the density after the ink absorption was visually checked and assessed based on the following criteria:
• Example 1 Example 2 2 3 4 5 Compounded component ⁇ Non-hydrophilic thermoplastic wt %/weight part 38/100 50/100 76/100 41/100 34/100 32/100 32/100 resin component> Polypropylene content ⁇ Hydrophilic resin> Species (abbrev.) — PEPO1 — PEPO1 PEPO1 PEPO1 PEPO1 Content wt %/weight part 12/32 — 24/32 9/22 16/43 18/56 8/56 ⁇ Fine powder> weight part 50 50 — 50 50 50 50 50 50 Content of calcium carbonate 1 ⁇ Dispersion modifier> Species (abbrev.) — — — — — — — — — Content weight part — — — — — — — — — Forming conditions Temperature a1 ° C.
• Example Example unit 13 14 15 Compounded Component ⁇ Non-hydrophilic wt %/weight 40/100 40/100 40/100 thermoplastic resin part component> Polypropylene content ⁇ Hydrophilic resin> Species (abbrev.) — PEPO1 PEPO1 PEPO1 Content wt %/weight 10/25 10/25 10/25 part ⁇ Fine powder> weight 50 50 50 Content of calcium part carbonate 2 Forming conditions Temperature a ° C. 250 250 250 250 Temperature b ° C. 50 50 50 Temperature c ° C. 154 154 154 Temperature d ° C. 155 155 Temperature e ° C.
• the porous resin films (Examples 1 to 12) of the present invention show excellent ink absorbing and drying properties even when the ink discharge is large, and also show a small non-uniformity in the printing density.
• the resin film containing no hydrophilic resin (Comparative Example 1) and the multi-layered stretched resin film containing no fine powder (Comparative Example 2) only showed a poor ink drying property and a large non-uniformity in the printing density.
• the porous resin film of the present invention (Example 10) was superior in the ink drying property and uniformity in the printing density to the film containing no hydrophilic resin
• the stacked material using the porous resin film of the present invention (Examples 13 to 15) also showed excellent ink absorbing and drying properties and a small non-uniformity in the printing density.
• a porous resin film of the present invention shows quite excellent ink absorbing and drying properties even when a large amount of ink is discharged thereon, and can be fabricated at a low cost.
• Using such porous resin film or a stacked material having such porous resin film stacked on a base layer can provide a recording medium capable of providing a high-definition image
• the present invention is widely applicable to various printing purposes and absorption base materials.

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• 1999
  • 1999-10-07 DE DE69943150T patent/DE69943150D1/de not_active Expired - Lifetime
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  • 1999-10-07 AT AT99970407T patent/ATE496085T1/de not_active IP Right Cessation
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• 2001
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